The invention relates to a process and apparatus for producing plastic-bound propellant powders and explosives by an extruder, comprising a casing with at least one draw or feed opening, optionally a solvent supply opening and at least one extruder screw shaft with kneading and conveying segments, the casing having at least one section transparent to UV/VIS or X-rays and a plastic binder polymerizable under these rays is supplied via the feed opening until the segments of the extruder shaft "float" without wall friction in the plastic binder and subsequently the components of the propellant powder or explosive material are added in crystalline form.
In, for example, German Pat. No. 30 44 577, DE-OS No. 32 42 301, and U.S. Pat. Nos. 4,525,813 and 4,608,210, it is proposed to build up monobasic, dibasic and also tribasic propellant powders, which all have a nitrocellulose base, into strand form by extrusion and then, by cutting, propelling compositions or propellant powders are produced therefore. In addition, propellant powders and explosives are known, which are bound in a plastic matrix. This involves the use of crystalline explosive materials, mainly hexogen, octogen or mixtures thereof (HMX-RDX) and/or nitroguanidine. It is also possible to add additives, such as nitrocellulose which improve the ignition behaviour in small amounts, together with other high-energy polymers. Previously, plastic-bound propellant powders and explosives could only be produced in batches, with the binder proportion being relatively high at approximately 15% and more.
By the process referred to hereinabove, and, more particularly, in U.S. Pat. No. 4,608,210 it is also possible to produce the aforementioned propellant powders or explosives with crystal grain in a plastic matrix by extrusion. Initially the plastic binder is added to the extruder in solid, dissolved or suspended form via the feed opening until the screw shafts "float" without reciprocal friction and wall friction in the plastic binder and this is followed by the addition of the components of the propellant powder or explosive material in crystalline form with a constantly increasing proportion, accompanied by a simultaneous decrease on the plastic binder proportion and finally the mixing ratio is kept constant. If addition takes place in dissolved or suspended form, precautions are taken for drawing off the solvent or suspension fluid, while on adding solid plastic binders within the extruder, a melting process is performed at temperatures up to max 130.degree. C. This makes it possible to produce propellant powders in strand form with channels or also explosives in strand form. During such processing of high-energy materials, particular care must be taken to avoid any metallic friction and that the process is performed in a completely satisfactory manner with regards temperature, pressure and polymerization rate. The first-mentioned risk is countered in that the extruder segments are initially "fed" with the plastic binder, so that friction between the segments and wall friction are excluded, in that the screw or screws are centered within the extruder. However, the other process control parameters cause certain problems if the polymerization processes exclusively take place at elevated temperature and/or in the multicomponent system and/or in the presence of catalysts. It has already been proposed in U.S. Pat. No. 4,608,210 to use plastic binders, whose polymerization takes place photochemically or under X-rays. For UV or VIS irradiation, particularly polymers with nitro groups, which are in turn considered as high-energy binders are suitable.